This invention relates to cylinders and, more specifically, to cylinders including stop tubes.
The use of stop tubes is a generally accepted and preferred method for reducing piston and bearing loads on long push stroke cylinders. It is also employed in the prevention of jackknifing or buckling of horizontally mounted long push stroke cylinders.
When employed for the purpose of reducing bearing loads on the rod, the use of stop tubes is more effective, less costly and results in a weight savings when compared to the use of oversized piston rods.
Typically, stop tubes are secured to either the piston or a cylinder head so as to restrict the extended position of the rod and increase the distance between the piston and a bushing typically employed in the head thereby providing additional strength and side support for the extended rod.
At the same time, stop tubes, because of the separation between the piston and the head when the piston is fully extended, reduce side loading in bushings caused by non-concentricity of the bushing in the head with respect to the rod on the piston within the cylinder, thereby extending bushing life.
Heretofore, such stop tubes have normally been welded on either the head or the piston. Expensive jigs have been required to provide such welding functions. In addition, such stop tubes necessarily must be discarded when the parts of the cylinder to which they are secured are discarded and replaced in the usual course of maintenance.